Why Next.js exists

Pure client-side React has two hard limits. Search engines and social media scrapers see an empty div on first load and have to wait for JavaScript to fill it in. And the user sees a blank screen until the JavaScript bundle loads and runs. Next.js moves the initial render to the server so the first page view is already populated.

SSR matters more for some apps than others. Public content sites live or die by SEO and initial paint. Internal dashboards behind a login rarely need it. Next.js lets you pick per page: some routes can be fully static, some server-rendered on every request, some purely client-side. One framework, every rendering model.